The human ability to store excess energy has contributed to an increased frequency of morbidly obese patients and those with Type 2 Diabetes. Patients having such conditions have increased morbidity and mortality resulting from associated co-morbidities, including cardiovascular disease and arthritis.
A sufficient release of Glucagon-Like Peptide (GLP-1), a known key hormone that regulates the body's glucose control hormone, is believed to alleviate Type 2 Diabetes and obesity. Normally, the presence of nutrients, which arise from a meal consisting of carbohydrates, fats and proteins, termed ‘digesta’ in the digestive tract, stimulates release of the body's own GLP-1 key hormone into the blood stream. Key hormones, released by specialized L-cells located in the mucosa, which is the innermost interior (luminal) wall of the intestines, coordinate the body's response to a meal. The hormones produce this effect by inducing a sense of fullness and cessation of eating (satiety), triggering the release of insulin to maintain proper glucose levels (incretin effect) and slowing the passage of contents through the digestive tract (delaying gastric emptying and slowing small intestinal transit). Altogether, these effects have been referred to as the “ileal brake” mechanism which involves both the hormones that play a role (such as PYY, GLP-1, and GLP-2, among others), as well as the multiplicity of effects of release of those hormones (gastric emptying, a feeling of fullness cessation of eating, triggering of insulin secretion).
An insufficient ileal brake, i.e., the inability of the body to release sufficient quantities of these hormones in response to a meal, is a contributory factor in obesity and Type 2 Diabetes. While in non-obese non-diabetic individuals fasting levels of GLP-1 are observed to be in the range of 5-10 pmol/L and to increase rapidly to 15-50 pmol/L after a meal, in T2D patients, the meal-related increase in GLP-1 is significantly less. The decreased insulin levels of such patients are attributable to an insufficient level of GLP-1. Similarly, also in obese subjects lower basal fasting hormone levels and smaller meal-associated rise of the hormone levels have been observed. Therefore, enhancing the body's endogenous levels of GLP-1 is believed to have impact on both obesity and diabetes.
There are known pharmaceutical means to increasing the endogenous active forms of GLP-1, e.g. by inhibition of its breakdown by dipeptidyl peptidase-4 (DPP-4) inhibitors, such as vildagliptin. In diabetic patients, improvement in glucose control is obtained by increasing the circulating levels of GLP-1 by vildagliptin.
As an alternative to pharmacological treatments, the most effective treatment for morbid obesity is bariatric surgery. A number of studies in patients after bariatric surgery suggest that there are increases in meal-related circulating GLP-1 levels after surgery, which contribute to the improvements in T2D and weight loss noted. However, bariatric surgery is perceived as a highly invasive measure recommended only for morbidly obese patients. A less invasive approach using a duodenal impermeable sleeve placed via an endoscope and fastened e.g. with a barbed metal anchor at the duodenal entrance has also shown to improve the glucose control.
It has been hypothesized that the manipulation of the intestine during and after surgery resulted in a stimulation of the mucosa which resulted in an increased release of the satiety hormone(s). US2010/0056948 describes a method of stimulating the release of satiety hormones in a subject comprising applying an electrical stimulus to a tissue in the gastrointestinal system of the subject contemporaneously with the contacting of L-cells of the tissue with a nutrient stimulus.
However, there remains still a need of an improved timing of the stimulation of the gastrointestinal system in relation with the food intake and the passage of the food bolus through the esophagus, stomach and intestine.
Currently available approaches for meal detection, such as HRV (heart rate variability) monitoring or detection of electrical signals in the duodenum are still to unspecific and indicate the ingestion of meal with too much delay for a precise electrical stimulation of the digestive system.
Also the proposed algorithms for so called artificial pancreas systems rely only on rough estimates of nutrition intake intervals which are indirectly derived from a continuous glucose metering and are calibrated to trigger a subcutaneous insulin administration in any case early enough to reach the blood stream in a timely manner.